Polyethylene sealing layer resins

Abstract

Embodiments of the present disclosure generally relate to polyethylene copolymer resins and methods thereof. In some embodiments, a polymer includes a polyethylene copolymer having ethylene units and comonomer units. The polyethylene copolymer includes a density of about 0.907 g / cm3 to about 0.913 g / cm3, wherein the density of the polyethylene copolymer is determined in accordance to ASTM D1505. The polyethylene copolymer further includes a melt index (I2) of about 4 g / 10 mm to about 8 g / 10 mm, wherein the I2 is determined in accordance to ASTM DI 238. The polyethylene copolymer further includes an olefin comonomer content of about 12.5 wt% to about 15 wt%.

Description

POLYETHYLENE SEALING LAYER RESINS CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims priority to and the benefit of U.S. Provisional Application No. 63 / 674,125 having a filing date of July 22, 2024, the disclosure of which is incorporated herein by reference in its entirety. FIELD

[0002] Embodiments of the present disclosure generally relate to polyethylene copolymer resins and methods thereof. BACKGROUND

[0003] Polyethylene copolymer resins are used in a variety of applications where the rheological and mechanical profiles of such materials dictate their end use and applications. As such, it is valuable to understand the multitude of variables, processes, and parameters which affect such properties of these materials during and throughout their production and processing.

[0004] In many instances, gas phase polymerization processes are utilized in the development of various polyethylene copolymer resins. In such processes, the use of Ziegler- Natta and metallocene catalysts have been well documented to produce polyethylene copolymer resins having low density, high tensile strength, high impact strength, high tear resistance, high stiffness, and high toughness. The gas phase processes have become commonplace in the production of polyethylene resins, and the resins produced can be implemented in the manufacture of multi-layer films.

[0005] However, such processes and catalysts used to form polyethylene copolymer resins useful as a sealing layer of a multi-layer film is rather challenging. In many instances, these polymerization processes are only capable of producing either high density polyethylene resins with high mechanical properties or low density polyethylene resins having suitable rheological profiles necessary for seal formation. In some instances, it may be desirable to produce polyethylene copolymer resins having both the high mechanical properties of the high density polyethylene resins and the rheological profiles of the low density polyethylene resins.

[0006] It may be desirable for the sealing layer of a multi-layer film to have both high mechanical performance, which complement the other layers of the multi-layer film at reduced temperatures, and suitable rheological profiles allowing for melt flow of the sealing layer at elevated temperatures. The rheological profile of a sealing layer influences its sealing ability, as the rheological profile describes the propensity of polymer chain mobility at a giventemperature. Polymer compositions used as sealing layers of multi-layer films typically have high chain mobility, which allows for intermixing of the polymer chains of two or more layers being brought together during the formation of a seal. Furthermore, the rheological profile of a sealing layer influences the layers seal caulkability, which is the ability of a molten resin to flow around small surface defects or contaminants to form a reliable seal between two films.

[0007] Unfortunately, processes and catalysts used in the formation polyethylene resins struggle to produce polyethylene copolymer resins having both the high mechanical properties and the rheological profiles suitable for a sealing layer of a multi-layer film. Balancing such material properties has been found to be challenging as previous attempts to do so can lead to sheeting of the polymer and catalyst system (e.g., material buildup) within a reactor and / or a reaction apparatus (e.g., gas-phase reactor). Such material sheeting may result in required reactor / reaction apparatus maintenance and / or downtime.

[0008] Some references of potential interest in this regard include: US 11,028,258; US 11,767,384; US 6,893,715; US 6,255,426; US 7,951,873; US 9,718,896; US 10,029,226; US 6,932,592; US 6,492,475; US 6,867,277; US 7,125,946; US 7,968,659; US 8,242,220; US 8,653,193; US 9,175,119; US 9,493,591; US 9,963,525; US 10,066,036; US 10,066,037; US 2004 / 0121098; US 2007 / 0260016; US 2015 / 0232589; US 2020 / 0339715; US 2018 / 0201705; US 2015 / 0232711; WO 2023 / 192846; KR 101740149 B1; KR 101689456 B1.

[0009] Overall, there is a need to develop processes that allow for the production of polyethylene copolymer resins having both the rheological and mechanical properties of a seal layer in addition to robust sealing ability. SUMMARY

[0010] Embodiments of the present disclosure generally relate to polyethylene copolymer resins and methods thereof.

[0011] In some embodiments, a polymer includes a polyethylene copolymer having ethylene units and comonomer units. The polyethylene copolymer includes a density of about 0.907 g / cm3to about 0.913 g / cm3, wherein the density of the polyethylene copolymer is determined in accordance to ASTM D1505. The polyethylene copolymer further includes a melt index (I2) of about 4 g / 10 min to about 8 g / 10 min, wherein the I2is determined in accordance to ASTM D1238. The polyethylene copolymer further includes an olefin comonomer content of about 12.5 wt% to about 15 wt%.

[0012] In some embodiments, a polymer film includes a sealing layer. The sealing layer includes a first polyethylene copolymer. The first polyethylene copolymer has a density of about 0.907 g / cm3to about 0.913 g / cm3, wherein the density of the first polyethylenecopolymer is determined in accordance to ASTM D1505. The first polyethylene copolymer also has a melt index (I2) of about 4 g / 10 min to about 8 g / 10 min, wherein the I2of the first polyethylene copolymer is determined in accordance to ASTM D1238. The first polyethylene copolymer also has an olefin comonomer content of about 12.5 wt% to about 15 wt%. The polymer film further includes a core layer disposed on the sealing layer. The core layer includes a second polyethylene copolymer. The polymer film further includes a skin layer disposed on the core layer. The skin layer includes a third polyethylene copolymer. The polymer film has a heat seal initiation temperature of about 60 ºC to about 70 ºC.

[0013] In some embodiments, a method of producing a polyethylene copolymer includes providing a feed stream to a reactor. The feed stream includes an ethylene monomer and an olefin comonomer. The olefin comonomer and ethylene monomer are provided to the reactor at a flow ratio of olefin comonomer:ethylene of about 0.15 lb / lb to about 0.18 lb / lb. The method further includes providing H2 gas to the reactor. The concentration of H2 gas provided to the reactor is about 330 ppm to about 390 ppm. The method further includes introducing a catalyst composition to the reactor. The catalyst composition is introduced into the reactor at a catalyst feed rate of about 4 g / hr to about 10 g / hr. The method further includes polymerizing the ethylene monomer and olefin comonomer. The reactor is operated at a temperature of about 50 °C to about 100 °C and a pressure of about 250 psig to about 350 psig. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this disclosure and are therefore not to be considered limiting of its scope, for the disclosure may admit to other equally effective embodiments.

[0015] Figure 1 is a schematic flow diagram of a gas phase reactor, according to an embodiment.

[0016] Figure 2 is a graph depicting the complex viscosities of certain polyethylene copolymer resins, as measured by small angle oscillatory shear measurements, according to an embodiment.

[0017] Figure 3 is a graph depicting the comonomer composition of certain polyethylene copolymer resins as a function of molecular weight, as measured by triple detector gel permeation chromatography, according to an embodiment.

[0018] Figure 4 is a graph depicting the elution temperature distribution of certain polyethylene copolymer resins, as measured by temperature rising elution fractionation, according to an embodiment.

[0019] Figure 5A is a graph depicting the heat seal strength of certain polymer films, according to an embodiment.

[0020] Figure 5B is a graph depicting the hot tack strength of certain polymer films, according to an embodiment.

[0021] Figure 6A is a graph depicting the heat seal strength of certain polymer films, according to an embodiment.

[0022] Figure 6B is a graph depicting the hot tack strength of certain polymer films, according to an embodiment.

[0023] Figure 7A is a graph depicting the heat seal strength of certain polymer films, according to an embodiment.

[0024] Figure 7B is a graph depicting the hot tack strength of certain polymer films, according to an embodiment.

[0025] Figure 8A is a graph depicting the heat seal strength of certain polymer films, according to an embodiment.

[0026] Figure 8B is a graph depicting the hot tack strength of certain polymer films, according to an embodiment.

[0027] Figure 9A is a graph depicting the heat seal strength of certain polymer films, according to an embodiment.

[0028] Figure 9B is a graph depicting the hot tack strength of certain polymer films, according to an embodiment. DETAILED DESCRIPTION

[0029] Embodiments of the present disclosure generally relate to polyethylene copolymer resins and methods thereof. Polyethylene resins used as a sealing layer of a multi-layer film have a low seal initiation temperature, while also maintaining the mechanical and rheological properties for manufacturing articles, such as multi-layer films. As such, processes have been developed that provide for the production of polyethylene copolymer resins having a macromolecular design (e.g., broad orthogonal comonomer distribution) that reduces the seal initiation temperature while still maintaining a sufficiently high density that is favorable to render the material with the physical and mechanical properties for integration within a multi- layer film. Furthermore, polyethylene copolymer resins of the present disclosure can exhibitrheological behaviors (e.g., low melt index ratio offset by a low molecular weight) suitable for both material processing (e.g., extrusion based processes) and seal formation.

[0030] As used herein, an “olefin,” alternatively referred to as “alkene,” is a linear, branched, or cyclic compound of carbon and hydrogen having at least one double bond. For purposes of this specification and the claims appended thereto, when a polymer or copolymer is referred to as “comprising” an olefin, the olefin present in such polymer or copolymer is the polymerized form of the olefin. For example, when a copolymer is described as having an “ethylene” content of 35 wt % to 55 wt %, it is understood that the mer unit in the copolymer is derived from ethylene in the polymerization reaction and the derived units are present at 35 wt % to 55 wt %, based upon the weight of the copolymer.

[0031] As used herein, the terms “polyethylene polymer,” “polyethylene,” “ethylene polymer,” “ethylene copolymer,” and “ethylene based polymer” mean a polymer or copolymer comprising at least 50 mol % ethylene units, or at least 70 mol % ethylene units, or at least 80 mol % ethylene units, or at least 90 mol % ethylene units, or at least 95 mol % ethylene units or 100 mol % ethylene units (in the case of a homopolymer).

[0032] As used herein, a “polymer” may refer to homopolymers, copolymers, interpolymers, terpolymers, etc. A “polymer” has two or more of the same or different monomer units. A “homopolymer” is a polymer having monomer units that are the same. A “copolymer” is a polymer having two or more monomer units that are different from each other. A “terpolymer” is a polymer having three monomer units that are different from each other. The term “different” as used to refer to monomer units indicates that the monomer units differ from each other by at least one atom or are different isomerically. Accordingly, the definition of copolymer, as used herein, includes terpolymers and the like. Likewise, the definition of polymer, as used herein, includes copolymers and the like.

[0033] As used herein, an ethylene polymer having a density of 0.910 to 0.925 g / cm3is referred to as a “linear low density polyethylene” (LLDPE) when substantially linear (having minor or no long chain branching) as is typically the case for Ziegler-Nata or metallocene- catalyzed PE or branched low density polyethylene (LDPE) when significantly branched (having a high degree of long chain branching), as is often the case with free-radical polymerized PE. Density is determined according to ASTM D792. Specimens are prepared according to ASTM D4703 – Annex 1 Procedure C followed by conditioning according to ASTM D618 – Procedure A prior to testing.

[0034] As used herein, and unless otherwise specified, the term “Cn” means hydrocarbon(s) having n carbon atom(s) per molecule, wherein n is a positive integer.

[0035] As used herein, and unless otherwise specified, the term “hydrocarbon” means a class of compounds containing hydrogen bound to carbon, and encompasses (i) saturated hydrocarbon compounds, (ii) unsaturated hydrocarbon compounds, and (iii) mixtures of hydrocarbon compounds (saturated or unsaturated), including mixtures of hydrocarbon compounds having different values of n.

[0036] As used herein, the term “film” refers to a continuous, flat (in some instances, flexible) polymeric structure having an average thickness of a range of 0.1, or 1, or 5, or 10, or 15, or 20 m to50, or 75, or 100, or 150, or 200, or 250, or 1000, or 2000 m, or such a coating of similar thickness adhered to a flexible, non-flexible or otherwise solid structure. The “film” may be made from or contain a single layer or multiple layers. Each layer may be made from or contain the polyethylene copolymers of the present disclosure. For example, one or more layers of a “film” may include a mixture of the disclosed polyethylene copolymer as well as a LDPE, another LLDPE, polypropylene, or a plastomer.

[0037] As used herein, the term “polymerizable conditions” refers to conditions conducive to the reaction of one or more olefin monomers when contacted with an activated olefin polymerization catalyst to produce a polyolefin polymer, including a skilled artisan’s selection of temperature, pressure, reactant concentrations, optional solvent / diluents, reactant mixing / addition parameters, and other conditions within at least one polymerization reactor.

[0038] For the sake of brevity, only certain ranges are explicitly disclosed herein. However, ranges from any lower limit may be combined with any upper limit to recite a range not explicitly recited, as well as, ranges from any lower limit may be combined with any other lower limit to recite a range not explicitly recited, in the same way, ranges from any upper limit may be combined with any other upper limit to recite a range not explicitly recited. Thus, every point or individual value may serve as its own lower or upper limit combined with any other point or individual value or any other lower or upper limit, to recite a range not explicitly recited.

[0039] The term “terminal olefin” refers to an olefin having a terminal carbon-to-carbon double bond in the structure thereof ((R1R2)-C=CH2, where R1and R2can be independently hydrogen or any hydrocarbyl group, such as R1is hydrogen, and R2is an alkyl group). A “linear terminal olefin” is a terminal olefin defined in this paragraph wherein R1is hydrogen, and R2is hydrogen or a linear alkyl group.

[0040] The term “vinyl” means an olefin having the following formula: ,wherein R is a hydrocarbyl group, such as a saturated hydrocarbyl group such as an alkyl group.

[0041] The term “vinylidene” means an olefin having the following formula: ; wherein R1and R2are each, group, such as a saturated hydrocarbyl group such as alkyl group.

[0042] The term “catalyst component” includes any compound that, once appropriately activated, is capable of catalyzing the polymerization or oligomerization of olefins. Preferably, the catalyst component can include at least one Group 3 to Group 12 atom and optionally at least one leaving group bound thereto.

[0043] The term "leaving group" refers to one or more chemical moieties bound to the metal center of the catalyst component that can be abstracted from the catalyst component by an activator, thereby producing the species active towards olefin polymerization or oligomerization. Suitable activators are described in detail below.

[0044] As used herein, in reference to Periodic Table "Groups" of Elements, the “new” numbering scheme for the Periodic Table Groups is used as in the CRC Handbook of Chemistry and Physics (David R. Lide, ed., CRC Press 81sted.2000).

[0045] The term “substituted” means that the group following that term possesses at least one moiety in place of one or more hydrogens in any position, the moieties selected from such groups as halogen radicals (for example, Cl, F, Br), hydroxyl groups, carbonyl groups, carboxyl groups, amine groups, phosphine groups, alkoxy groups, phenyl groups, naphthyl groups, C1to C7 alkyl groups, C2 to C7 alkenyl groups, and combinations thereof. Examples of substituted alkyls and aryls includes, but are not limited to, acyl radicals, alkylamino radicals, alkoxy radicals, aryloxy radicals, alkylthio radicals, dialkylamino radicals, alkoxycarbonyl radicals, aryloxycarbonyl radicals, carbomoyl radicals, alkyl- and dialkyl- carbamoyl radicals, acyloxy radicals, acylamino radicals, arylamino radicals, and combinations thereof.

[0046] The term “catalyst system” includes at least one “catalyst component” and at least one “activator”, alternately at least one cocatalyst. The catalyst system can also include other components, such as supports, and is not limited to the catalyst component and / or activator alone or in combination. The catalyst system can include any number of catalyst components in any combination as described, as well as any activator in any combination as described. Polymer composition

[0047] The present disclosure provides polyethylene resins (e.g., linear polyethylene resins) having balanced physical and rheological properties. Polyethylene resins of the present disclosure may include broad comonomer distribution which can reduce the material’s seal initiation temperature while also maintaining sufficiently high material density so to as to provide stiffness and yield strength properties that can provide mechanical properties suitable for multi-layer films. The method(s) of the present disclosure can provide polyethylene compositions having a combination of a higher material density and either a low seal initiation temperature and / or a broad hot tack window (e.g., sealing temperature range for which the strength of a newly formed seal is above a usable threshold). In terms of sealing performance, hot tack is a measure of the strength of a heat seal immediately after the seal has been formed and before it cools to ambient temperature. Thus, having a broad tack window allows for reliable seal formation at a broad range of temperature profiles.

[0048] In some embodiments, the polyethylene resin is a polyethylene copolymer resin, such as a linear metallocene polyethylene copolymer resin. The polyethylene copolymer resin may include a polyethylene copolymer that is the polymerization product of an ethylene monomer and one or more olefin comonomers, such as alpha-olefin comonomers. Alpha-olefin comonomers can have 3 to 12 carbon atoms, or from 4 to 10 carbon atoms, or from 4 to 8 carbon atoms. Olefin comonomers can be selected from propylene, 1-butene, 1-pentene, 1- hexene, 1-heptene, 1-octene, 4-methylpent-1-ene, 1-nonene, 1-decene, 1-undecene, 1- dodecene, 1-hexadecene, and the like, and any combination thereof, such as 1-butene, 1- hexene, and / or 1-octene. In some embodiments, a polyene is used as a comonomer. In some embodiments, the polyene is selected from the group consisting of 1,3-hexadiene, 1,4- hexadiene, cyclopentadiene, dicyclopentadiene, 4-vinylcyclohex-1-ene, methyloctadiene, 1- methyl-1,6-octadiene, 7-methyl- 1,6-octadiene, 1,5-cyclooctadiene, norbornadiene, ethylidene norbornene, 5-vinylidene-2-norbornene, 5-vinyl-2-norbornene, and olefins formed in situ in the polymerization medium. In some embodiments, comonomers are selected from isoprene, styrene, butadiene, isobutylene, chloroprene, acrylonitrile, and cyclic olefins. In some embodiments, combinations of the olefin comonomers are utilized. In some embodiments, the olefin comonomer is selected from 1-butene and 1-hexene. In at least one embodiment, the olefin comonomer is integrated into the polyethylene copolymer composition in an amount of about 0.1 wt% to about 20 wt% based on the total weight of olefin comonomer in the polyethylene copolymer, such as about 10 wt% to about 20 wt%, such as about 12 wt% to about 18 wt%, such as about 12.5 wt% to about 15 wt%, such as about 13 wt% to about 14 wt%, alternatively about 10 wt% to about 12 wt%, alternatively about 12 wt% to about 12.5 wt%,alternatively about 12.5 wt% to about 13 wt%, alternatively about 13 wt% to about 13.5 wt%, alternatively about 13.5 wt% to about 14 wt%, alternatively about 14 wt% to about 15 wt%, alternatively about 15 wt% to about 18 wt%, alternatively about 18 wt% to about 20 wt%. The balance of the polyethylene comonomer is made up of units derived from ethylene such that the polyethylene copolymer includes about 80 wt% to about 99.9 wt% ethylene units, such as about 80 wt% to about 90 wt%, such as about 82 wt% to about 88 wt%, such as about 85 wt% to about 87.5 wt%, such as about 86 wt% to about 87 wt%, alternatively about 80 wt% to about 82 wt%, alternatively about 82 wt% to about 85 wt%, alternatively about 86 wt% to about 86 wt%, alternatively about 86 wt% to about 86.5 wt%, alternatively about 86.5 wt% to about 87 wt%, alternatively about 87 wt% to about 87.5 wt%, alternatively about 87.5 wt% to about 88 wt%, alternatively about 88 wt% to about 90 wt%.

[0049] In some embodiments, the polyethylene copolymer resin includes a number average molecular weight (Mn), as determined by polymer char gel permeation chromatography equipped with multiple detectors (GPC4D), of about 20 kDa to about 40 kDa, such as about 25 kDa to about 35 kDa, such as about 27.5 kDa to about 32.5 kDa, alternatively about 20 kDa to about 25 kDa, alternatively about 25 kDa to about 27.5 kDa, alternatively about 27.5 kDa to about 30, alternatively about 30 kDa to about 32.5 kDa, alternatively about 32.5 kDa to about 35 kDa, alternatively about 35 kDa to about 40 kDa. In some embodiments, the polyethylene copolymer resin includes a weight average molecular weight (Mw), as determined by GPC4D, of about 60 kDa to about 90 kDa, such as about 65 kDa to about 85 kDa, such as about 70 kDa to about 80 kDa, alternatively about 60 kDa to about 65 kDa, alternatively about 65 kDa to about 70 kDa, alternatively about 70 kDa to about 75 kDa, alternatively about 75 kDa to about 80 kDa, alternatively about 80 kDa to about 85 kDa, alternatively about 85 kDa to about 90 kDa. In some embodiments, the polyethylene copolymer resin includes a z average molecular weight (Mz), as determined by GPC4D, of about 110 kDa to about 140 kDa, such as about 115 kDa to about 135 kDa, such as about 120 kDa to about 130 kDa, alternatively about 110 kDa to about 115 kDa, alternatively about 115 kDa to about 120 kDa, alternatively about 120 kDa to about 125 kDa, alternatively about 125 kDa to about 130 kDa, alternatively about 130 kDa to about 135 kDa, alternatively about 135 kDa to about 140 kDa. In some embodiments, the polyethylene copolymer resin includes a molecular weight distribution (MWD), as determined by GPC4D, of about 2.0 to about 5.0, such as about 2.0 to about 4.0, such as about 2.0 to about 3.0, such as about 2.0 to about 2.75, such as about 2.0 to about 2.6, such as about 2.0 to about 2.5, such as about 2.0 to about 2.4, such as about 2.0 to about 2.3, such as about 2.0 to about 2.2, such as about 2.0 to about 2.15. In some embodiments, the polyethylene copolymer resinincludes a MWD, as determined by GPC4D, of about 2.0 to about 4.0, such as about 2.5 to about to about 3.5, such as about 2.5 to about 3.0, such as about 2.5 to about 2.75, such as about 2.6 to about 2.75.

[0050] In some embodiments, the polyethylene copolymer resin includes a broad orthogonal composition distribution (BOCD), meaning that a large percentage of the olefin comonomer integrated within the polyethylene copolymer resin is predominantly located along the polymeric backbone (e.g., covalently bound within the polymeric backbone) of larger molecular weight polymer chains present in the polyethylene copolymer resin. In other words, the olefin comonomer integrated within the polyethylene copolymer resin is concentrated on the high molecular weight population of the resin. Furthermore, one of ordinary skill would appreciate that the high molecular weight population of the polyethylene copolymer resin has a higher viscosity than the viscosity of the low molecular weight population. Without being bound by theory, the compositional orientation of the polyethylene copolymer resin is surmised to improve the hot tack performance of the resin by allowing the higher viscosity, high molecular weight portion of the resin to melt at a lower temperature profile.

[0051] In at least one embodiment, the BOCD of the polyethylene copolymer resin can be characterized by its T75-T25 value determined using temperature rising elution fraction (TREF) analysis as described below, wherein T25 is the temperature at which 25% of the eluted polymer is obtained and T75is the temperature at which 75% of the eluted polymer is obtained in a TREF experiment as described in WO2019 / 083609. In at least one embodiment, the BOCD of the polyethylene copolymer resin can be characterized by its M60 / M90value determined using TREF analysis as described below, wherein 60 is the molecular weight of the polymer fraction that elutes at 60°C in a TREF light scattering (TREF-LS) experiment and M90is the molecular weight of the polymer fraction that elutes at 90°C in a TREF-LS experiment. In at least one embodiment, the BOCD of the polyethylene copolymer resin can be characterized by its F80value determined using TREF analysis as described below, wherein F80 is the weight fraction of polymer that elutes below 80 °C in an TREF-LS experiment.

[0052] In some embodiments, the polyethylene copolymer resin has a T75-T25 value of about 1 °C or greater, such as about 2 °C or greater, such as about 2.5 °C or greater, such as about 4 °C or greater, such as about 5 °C or greater, such as about 7 °C or greater, such as about 10 °C or greater, such as about 11.5 °C or greater, such as about 15 °C or greater, such as about 17.5 °C or greater, such as about 20 °C or greater, such as about 25 °C or greater, such as about 30 °C or greater, such as about 35 °C or greater, such as about 40 °C or greater, or such as about 45 °C or greater, alternatively about 1 °C to about 45 °C, alternatively about 5 °C to about 30°C, alternatively about 10 °C to about 25 °C, alternatively about 11.5 °C to about 20 °C. In some embodiments, the polyethylene copolymer resin has a M60 / M90value of about 1.5 or greater, such as about 2 or greater, such as about 2.25 or greater, such as about 2.5 or greater, such as about 3 or greater, such as about 3.5 or greater, such as about 4 or greater, such as about 4.5 or greater, such as about 5 or greater, such as about 20, such as to about 10. In some embodiments, the polyethylene copolymer resin has a F80value of about 1% or greater, such as about 2% or greater, such as about 3% or greater, such as about 4% or greater, such as about 5% or greater, such as about 6% or greater, such as about 7% or greater, such as about 10% or greater, such as about 11% or greater, such as about 12% or greater, such as about 15% or greater. Polymer properties

[0053] In some embodiments, the polyethylene copolymer resin has a density of about 0.9 g / cm3to about 0.92 g / cm3, such as about 0.905 g / cm3to about 0.915 g / cm3, such as about 0.907 g / cm3to about 0.913 g / cm3, alternatively about 0.9 g / cm3to about 0.905 g / cm3, alternatively about 0.905 g / cm3to about 0.907 g / cm3, alternatively about 0.907 g / cm3to about 0.91 g / cm3, alternatively about 0.91 g / cm3to about 0.913 g / cm3, alternatively about 0.913 g / cm3to about 0.915 g / cm3, alternatively about 0.915 g / cm3to about 0.92 g / cm3. In some embodiments, the polyethylene copolymer resin includes a melt index (I2) of about 3 g / 10 min to about 9 g / 10 min, such as about 4 g / 10 min to about 8 g / 10 min, such as about 5 g / 10 min to about 7 g / 10 min, alternatively about 3 g / 10 min to about 4 g / 10 min, alternatively about 4 g / 10 min to about 5 g / 10 min, alternatively about 5 g / 10 min to about 6 g / 10 min, alternatively about 6 g / 10 min to about 7 g / 10 min, alternatively about 7 g / 10 min to about 8 g / 10 min, alternatively about 8 g / 10 min to about 9 g / 10 min. In some embodiments, the polyethylene copolymer resin includes a high load melt index (I21) of about 60 g / 10 min to about 140 g / 10 min as determined in accordance to ASTM D1238 (190°C, 21.6 kg load), such as about 80 g / 10 min to about 120 g / 10 min, such as about 90 g / 10 min to about 110 g / 10 min, alternatively about 60 g / 10 min to about 80 g / 10 min, alternatively about 80 g / 10 min to about 90 g / 10 min, alternatively about 90 g / 10 min to about 100 g / 10 min, alternatively about 100 g / 10 min to about 110 g / 10 min, alternatively about 110 g / 10 min to about 120 g / 10 min, alternatively about 120 g / 10 min to about 140 g / 10 min. In some embodiments, the polyethylene copolymer resin includes a melt index ratio (MIR) of about 15 to about 25, such as about 16 to about 20, such as about 17 to about 18.

[0054] In some embodiments, the polyethylene copolymer resin includes a complex shearviscosity ( *) of about 800 Pa to about 2000 Pa at a frequency of 0.01 rad / s, such as about 1000Pa to about 1800 Pa, such as about 1200 Pa to about 1500 Pa, alternatively about 800 Pa to about 1000 Pa, alternatively about 1000 Pa to about 1200 Pa, alternatively about 1200 Pa to about 1500 Pa, alternatively about 1500 Pa to about 1800 Pa, alternatively about 1800 Pa to about 2000 Pa.

[0055] In some embodiments, the polyethylene copolymer resin includes a shear thinning ratio of about 1.4 to about 1.7, such as about 1.5 to about 1.6, such as about 1.525 to about 1.575, alternatively about 1.4 to about 1.5, alternatively about 1.5 to about 1.525, alternatively about 1.525 to about 1.5, alternatively about 1.5 to about 1.575, alternatively about 1.575 to about 1.6, alternatively about 1.6 to about 1.7. Reactor

[0056] The polymerization process can include a gas phase polymerization reaction, and in particular a fluidized bed gas phase polymerization reaction. The gas-phase polymerization may be carried out in any suitable reactor system, e.g., a stirred- or paddle-type reactor system. See U.S. Pat. Nos. 7,915,357; 8,129,484; 7,202,313; 6,833,417; 6,841,630; 6,989,344; 7,504,463; 7,563,851; and 8,101,691 for discussion of suitable gas phase fluidized bed polymerization systems, which are well known in the art.

[0057] In polymerization processes of the present disclosure, a gas-phase, fluidized-bed process can be conducted by passing a feed stream containing ethylene and an olefin comonomer continuously through a fluidized-bed reactor under reaction conditions and in the presence of a catalyst composition at a velocity sufficient to maintain a bed of solid particles in a suspended state. A stream (which may be called a “cycle gas” stream) containing unreacted ethylene and olefin comonomer is continuously withdrawn from the reactor, compressed, cooled, optionally partially or fully condensed, and recycled back to the reactor. Prepared polyethylene copolymer is withdrawn from the reactor and replacement ethylene and olefin comonomer are added to the recycle stream. In some embodiments, gas inert to the catalyst composition and reactants is present in the gas stream.

[0058] The feed stream can include induced condensing agents (ICA). An ICA is one or more non-reactive alkanes that are condensable in the polymerization process for removing the heat of reaction. In some embodiments, the non-reactive alkanes are selected from C1-C6alkanes, e.g., one or more of propane, butane, isobutane, pentane, isopentane, hexane, as well as isomers thereof and derivatives thereof. In some instances, mixtures of two or more such ICAs may be particularly desirable (e.g., propane and pentane, propane and butane, butane and pentane, etc.).

[0059] Figure 1 depicts a flow diagram of an illustrative gas phase system 100 that can be used to make the polyethylene copolymers disclosed herein. The system 100 can include a single reactor 140 in fluid communication with one or more discharge tanks 155, surge tanks 160, recycle compressors 170, and heat exchangers 175. For simplicity and ease of description, embodiments of the invention will be further described in the context of a single reactor train.

[0060] In one or more embodiments, the reactor 140 can include a reaction zone 145 in fluid communication with a velocity reduction zone 150. The reaction zone 145 can include a bed of growing polymer particles, formed polymer particles and catalyst particles fluidized by the continuous flow of polymerizable and modifying gaseous components in the form of make- up feed and recycle fluid through the reaction zone 145.

[0061] A feed stream or make-up stream 110 can be introduced into the polymerization system at any point. For example, the feed stream or make-up stream 110 can be introduced to the reactor fluid bed in the reaction zone 145 or to the expanded section 150 or to any point within the recycle stream 115. Preferably, the feed stream or make-up stream 110 is introduced to the recycle stream 115 before or after the heat exchanger 175.

[0062] The fluidized bed can have the general appearance of a dense mass of moving particles as created by the percolation of gas through the bed. The pressure drop through the bed is equal to or slightly greater than the weight of the bed divided by the cross-sectional area. It is thus dependent on the geometry of the reactor. To maintain a viable fluidized bed in the reaction zone 145, the superficial gas velocity through the bed must exceed the minimum flow required for fluidization. Preferably, the superficial gas velocity is at least two times the minimum flow velocity. Ordinarily, the superficial gas velocity does not exceed 1.52 m / sec and usually no more than 0.762 m / sec is sufficient.

[0063] In general, the height to diameter ratio of the reaction zone 145 can vary in the range of from about 2:1 to about 5:1. The range, of course, can vary to larger or smaller ratios and depends upon the desired production capacity. The cross-sectional area of the velocity reduction zone 150 is typically within the range of about 2 to about 3 multiplied by the cross- sectional area of the reaction zone 145.

[0064] The velocity reduction zone 150 can have a larger inner diameter than the reaction zone 145. As the name suggests, the velocity reduction zone 150 can slow the velocity of the gas due to the increased cross-sectional area. This reduction in gas velocity can allow particles entrained in the upward moving gas to fall back into the bed, allowing primarily only gas to exit overhead of the reactor 140 through recycle gas stream 115.

[0065] The recycle stream 115 can be compressed in the compressor 170 and then passed through the heat exchanger 175 where heat is removed before it is returned to the bed. The heat exchanger 175 can be of the horizontal or vertical type. If desired, several heat exchangers can be employed to lower the temperature of the cycle gas stream in stages. It is also possible to locate the compressor downstream from the heat exchanger or at an intermediate point between several heat exchangers. After cooling, the recycle stream 115 can be returned to the reactor 140. The cooled recycle stream can absorb the heat of reaction generated by the polymerization reaction. In one or more embodiments above or elsewhere herein, condensing mode operation, such as described in US Pat. Nos. 4,543,399; 4,588,790; 5,352,749; and 5,462,999, can be used to assist in heat removal from the reactor 140.

[0066] In one or more embodiments, the recycle stream 115 can be returned to the reactor 140 and to the fluidized bed through a gas distributor plate 180. A gas deflector 185 is preferably installed at the inlet to the reactor to prevent contained polymer particles from settling out and agglomerating into a solid mass and to prevent liquid accumulation at the bottom of the reactor as well to facilitate easy transitions between processes which contain liquid in the cycle gas stream and those which do not and vice versa. An illustrative deflector suitable for this purpose is described in US Pat. Nos.4,933,149 and 6,627,713.

[0067] The catalyst or catalyst system can be introduced to the fluidized bed within the reactor 140 through the one or more injection nozzles 130. The catalyst or catalyst system is preferably introduced as pre-formed particles in one or more liquid carriers (e.g., a catalyst slurry). Suitable liquid carriers include mineral oil and liquid hydrocarbons including but not limited to propane, butane, isopentane, hexane, heptane, and octane, or mixtures thereof. A gas that is inert to the catalyst slurry such as, for example, nitrogen or argon can also be used to carry the catalyst slurry into the reactor 140. In one or more embodiments, the catalyst or catalyst system can be a dry powder. In one or more embodiments, the catalyst or catalyst system can be dissolved in the liquid carrier and introduced to the reactor 140 as a solution.

[0068] On discharge of particulate polymer product from reactor 140, it is desirable and preferable to separate fluid from the product and to return the fluid to the recycle line 115. In one or more embodiments, this separation can be accomplished when fluid and product leave the reactor 140 and enter the product discharge tanks 155 through valve 157, which can be a ball valve designed to have minimum restriction to flow when opened. Conventional valves 159 and 167 can be positioned above and below the product discharge tank 155. The valve 167 can allow passage of product into the product surge tanks 160.

[0069] In at least one embodiment, to discharge particulate polymer from reactor 140, valve 157 can be opened while valves 159 and 167 are in a closed position. Product and fluid can enter the product discharge tank 155. Valve 159 can be opened to allow the fluid to return to the reactor 140. Valve 157 can be closed, allowing the product to settle in the product discharge tank 155. Valve 159 can then be closed. Valve 167 can be opened and any product in the product discharge tank 155 flows into the product surge tank 160. Valve 167 can then be closed. Product can then be discharged from the product surge tank 160 through valve 164. The product can be further purged via purge stream 163 to remove residual hydrocarbons (and vented at 162) and conveyed to a pelletizing system or to storage. The particular timing sequence of the valves 157, 159, 167, and 164 can accomplished by the use of conventional programmable controllers which are well known in the art.

[0070] Another preferred product discharge system which can be alternatively employed is that disclosed and claimed in US Pat. No. 4,621,952. Such a system employs at least one (parallel) pair of tanks comprising a settling tank and a transfer tank arranged in series and having the separated gas phase returned from the top of the settling tank to a point in the reactor near the top of the fluidized bed.

[0071] The fluidized-bed reactor can be equipped with an adequate venting system (not shown) to allow venting the bed during start up and shut down. The reactor does not require the use of stirring and / or wall scraping. The recycle line 115 and the elements therein (compressor 170 and heat exchanger 175) can be smooth surfaced and devoid of unnecessary obstructions so as not to impede the flow of recycle fluid or entrained particles. Reactor conditions

[0072] In some embodiments, the reactor is operated at a pressure of about 100 psig to about 500 psig during the polymerization reaction, such as about 150 psig to about 450 psig, such as about 200 psig to about 400 psig, such as about 250 psig to about 350 psig, alternatively about 100 psig to about 150 psig, alternatively about 150 psig to about 200 psig, alternatively about 200 psig to about 250 psig, alternatively about 250 psig to about 300 psig, alternatively about 300 psig to about 350 psig, alternatively about 350 psig to about 400 psig, alternatively about 400 psig to about 450 psig, alternatively about 450 psig to about 500 psig. In some embodiments, the reactor is operated at a temperature of about 50 °C to about 100 °C during the polymerization process, such as about 60 °C to about 90 °C, such as about 70 °C to about 80 °C, alternatively about 50 °C to about 60 °C, alternatively about 60 °C to about 70 °C, alternatively about 70 °C to about 75 °C, alternatively about 75 °C to about 80 °C, alternatively about 80 °C to about 90 °C, alternatively about 90 °C to about 100 °C.

[0073] In some embodiments, the ethylene concentration provided to the reactor is about 45 mol% to about 75 mol% based on the total mol% of each of the components (e.g., ethylene, olefin comonomer, H2 gas, N2 gas, catalyst, and ICA) provided to the reactor, such as about 50 mol% to about 70 mol%, such as about 55 mol% to about 65 mol%, alternatively about 45 mol% to about 50 mol%, alternatively about 50 mol% to about 55 mol%, alternatively about 55 mol% to about 60 mol%, alternatively about 60 mol% to about 65 mol%, alternatively about 65 mol% to about 70 mol%, alternatively about 70 mol% to about 75 mol%. In some embodiments, the pressure within the reactor due to the concentration of ethylene therein (e.g., the ethylene partial pressure) is about 150 psi to about 210 psi, such as about 160 psi to about 200 psi, such as about 170 psi to about 190 psi, alternatively about 150 psi to about 160 psi, alternatively about 160 psi to about 170 psi, alternatively about 170 psi to about 180 psi, alternatively about 180 psi to about 190 psi, alternatively about 190 psi to about 200 psi, alternatively about 200 psi to about 210 psi.

[0074] In some embodiments, the H2gas concentration provided to the reactor is about 300 ppm to about 5,000 ppm, such as about 300 ppm to about 2,500 ppm, such as about 300 ppm to about 1,000 ppm, such as about 300 ppm to about 500 ppm. In some embodiments, the H2 gas concentration provided to the reactor is about 330 ppm to about 390 ppm, such as about 340 ppm to about 380 ppm, such as about 350 ppm to about 370 ppm, alternatively about 330 ppm to about 340 ppm, alternatively about 340 ppm to about 350 ppm, alternatively about 350 ppm to about 360 ppm, alternatively about 360 ppm to about 370 ppm, alternatively about 370 ppm to about 380 ppm, alternatively about 380 ppm to about 390 ppm. In some embodiments, the gas ratio of H2:ethylene provided to the reactor is about 5 mol ppm to about 100 mol ppm, such as about 5 mol ppm to about 50 mol ppm, such as about 5 mol ppm to about 25 mol ppm. In some embodiments, the gas ratio of H2:ethylene provided to the reactor during the polymerization reaction is about 5 mol ppm to about 7 mol ppm, such as about 5.5 mol ppm to about 6.5 mol ppm, such as about 5.75 mol ppm to about 6.25 mol ppm, alternatively about 5 mol ppm to about 5.5 mol ppm, alternatively about 5.5 mol ppm to about 5.75 mol ppm, alternatively about 5.75 mol ppm to about 6 mol ppm, alternatively about 6 mol ppm to about 6.25 mol ppm, alternatively about 6.25 mol ppm to about 6.5 mol ppm, alternatively about 6.5 mol ppm to about 7 mol ppm.

[0075] In some embodiments, the olefin comonomer concentration provided to the reactor is about 0.2 mol% to about 1 mol% based on the total mol% of each of the components (e.g., ethylene, olefin comonomer, H2gas, N2gas, catalyst, and ICA) provided to the reactor, such as about 0.4 mol% to about 0.8 mol%, such as about 0.5 mol% to about 0.7 mol%, alternativelyabout 0.2 mol% to about 0.4 mol%, alternatively about 0.4 mol% to about 0.5 mol%, alternatively about 0.5 mol% to about 0.6 mol%, alternatively about 0.6 mol% to about 0.7 mol%, alternatively about 0.7 mol% to about 0.8 mol%, alternatively about 0.8 mol% to about 1 mol%. In some embodiments, the gas ratio of the olefin comonomer:ethylene provided to the reactor is about 0.01 mol / mol to about 5 mol / mol, such as about 0.01 mol / mol to about 2.5 mol / mol, such as about 0.01 mol / mol to about 1 mol / mol. In some embodiments, the gas ratio of the olefin comonomer:ethylene provided to the reactor is about 0.02 mol / mol to about 0.04 mol / mol, such as about 0.025 mol / mol to about 0.035 mol / mol, such as about 0.028 mol / mol to about 0.032 mol / mol, alternatively about 0.02 mol / mol to about 0.025 mol / mol, alternatively about 0.025 mol / mol to about 0.028 mol / mol, alternatively about 0.028 mol / mol to about 0.03 mol / mol, alternatively about 0.03 mol / mol to about 0.032 mol / mol, alternatively about 0.032 mol / mol to about 0.035 mol / mol, alternatively about 0.035 mol / mol to about 0.04 mol / mol. In at least one embodiment, the flow ratio of the olefin comonomer:ethylene provided to the reactor about 0.1 lb / lb to about 5 lb / lb, such as about 0.1 lb / lb to about 2.5 lb / lb, such as about 0.1 lb / lb to about 1 lb / lb. In at least one embodiment, the flow ratio of the olefin comonomer:ethylene provided to the reactor about 0.15 lb / lb to about 0.18 lb / lb, such as about 0.155 lb / lb to about 0.175 lb / lb, such as about 0.16 lb / lb to about 0.17 lb / lb, alternatively about 0.15 lb / lb to about 0.155 lb / lb, alternatively about 0.155 lb / lb to about 0.16 lb / lb, alternatively about 0.16 lb / lb to about 0.165 lb / lb, alternatively about 0.165 lb / lb to about 0.17 lb / lb, alternatively about 0.17 lb / lb to about 0.175 lb / lb, alternatively about 0.175 lb / lb to about 0.18 lb / lb.

[0076] In some embodiments, the ICA concentration provided to the reactor is about 1.5 mol% to about 3 mol% based on the total mol% of each of the components (e.g., ethylene, olefin comonomer, H2 gas, N2 gas, catalyst, and ICA) provided to the reactor, such as about 1.75 mol% to about 2.75 mol%, such as about 2 mol% to about 2.5 mol%, alternatively about 1.5 mol% to about 1.75 mol%, alternatively about 1.75 mol% to about 2 mol%, alternatively about 2 mol% to about 2.25 mol%, alternatively about 2.25 mol% to about 2.5 mol%, alternatively about 2.5 mol% to about 2.75 mol%, alternatively about 2.75 mol% to about 3 mol%. In some embodiments, the N2gas concentration provided to the reactor is about 25 mol% to about 50 mol% based on the total mol% of each of the components (e.g., ethylene, olefin comonomer, H2gas, N2gas, catalyst, and ICA) provided to the reactor, such as about 30 mol% to about 45 mol%, such about 35 mol% to about 40 mol%, alternatively about 25 mol% to about 30 mol%, alternatively about 30 mol% to about 35 mol%, alternatively about 35 mol%to about 37.5 mol%, alternatively about 37.5 mol% to about 40 mol%, alternatively about 40 mol% to about 45 mol%, alternatively about 45 mol% to about 50 mol%.

[0077] In some embodiments, the components (e.g., ethylene, olefin comonomer, H2 gas, N2gas, catalyst, and ICA) of the polymerization reaction are maintained in the reactor for a residence time of about 2 hrs to about 6 hrs, such as about 3 hrs to about 5 hrs, such as about 3.5 hrs to about 4.5 hrs, alternatively about 2 hrs to about 3 hrs, alternatively about 3 hrs to about 4.5 hrs, alternatively about 4.5 hrs to about 5 hrs, alternatively about 5 hrs to about 6 hrs. In at least one embodiment, residence time defined as the reactor’s bed weight (e.g., the total weight of polymeric material in the reactor) divided by the reactor’s production rate (e.g., lbs / hr of polymeric material produced). Catalyst composition

[0078] According to some embodiments, the catalyst can include one or more metallocene catalyst components, also known as “metallocenes.” Suitable metallocenes are generally described throughout 1 & 2 Metallocene-Based Polyolefins (John Scheirs & W. Kaminsky, eds., John Wiley & Sons, Ltd. 2000); G.G. Hlatky in 181 Coordination Chem. Rev. 243-296 (1999), and in particular, for use in the synthesis of polyethylene in 1 Metallocene-Based Polyolefins 261-377 (2000), each of which is incorporated herein in its entirety. The metallocene catalyst compounds as described herein can include “half sandwich” and “full sandwich” compounds having one or more Cp ligands (cyclopentadienyl and ligands isolobal to cyclopentadienyl) bound to at least one Group 3 to Group 12 metal atom, and one or more leaving group(s) bound to the at least one metal atom. One particularly suitable metallocene is zirconocene containing a carbon to zirconium bond, which is commercially available from Univation Technologies, LLC under the tradename XCAT™. In at least one embodiment, the metallocene catalyst component can be supported on a support material and may be supported with or without another catalyst component.

[0079] The Cp ligands can be one or more rings or ring system(s), at least a portion of which includes -bonded systems, such as cycloalkadienyl ligands and heterocyclic analogues. The ring(s) or ring system(s) typically comprise atoms selected from the group consisting of Groups 13 to 16 atoms, or the atoms that make up the Cp ligands are selected from the group consisting of carbon, nitrogen, oxygen, silicon, sulfur, phosphorous, germanium, boron and aluminum and combinations thereof, wherein carbon makes up at least 50% of the ring members. Or the Cp ligand(s) can be selected from the group consisting of substituted and unsubstituted cyclopentadienyl ligands and ligands isolobal to cyclopentadienyl, non-limiting examples of which include cyclopentadienyl, indenyl, fluorenyl and other structures. Furthernon-limiting examples of such ligands include cyclopentadienyl, cyclopentaphenanthreneyl, indenyl, benzindenyl, fluorenyl, octahydrofluorenyl, cyclooctatetraenyl, cyclopentacyclododecene, phenanthrindenyl, 3,4-benzofluorenyl, 9-phenylfluorenyl, 8-H- cyclopent[a]acenaphthylenyl, 7H-dibenzofluorenyl, indeno[1,2-9]anthrene, thiophenoindenyl, thiophenofluorenyl, hydrogenated versions thereof (e.g., 4,5,6,7-tetrahydroindenyl, or “H4Ind”), substituted versions thereof, and heterocyclic versions thereof.

[0080] In at least one embodiment, the catalysts employed in the polymerization are metallocene catalysts. In particular, metallocene catalysts may be selected from the catalysts described in Patent Cooperation Treaty Publication Nos. WO1993008221, WO1996008520, WO1998044011, and WO2007130277, incorporated herein by reference. For instance, the catalysts may be silica-supported metallocene catalyst prepared from compositions comprising dimethylsilylbis(tetrahydroindenyl) zirconium dichloride metallocene and methylalumoxane cocatalyst. In some embodiments, a catalyst is dimethylsilylbis(tetrahydroindenyl) zirconium dichloride.

[0081] In at least one embodiment, the catalyst is fed into the reactor during the polymerization reaction process at a catalyst feed rate of about 4 g / hr to about 10 g / hr, such as about 5 g / hr to about 9 g / hr, such as about 6 g / hr to about 8 g / hr, alternatively about 4 g / hr to about 5 g / hr, alternatively about 5 g / hr to about 6 g / hr, alternatively about 6 g / hr to about 7 g / hr, alternatively about 7 g / hr to about 8 g / hr, alternatively about 8 g / hr to about 9 g / hr, alternatively about 9 g / hr to about 10 g / hr.

[0082] In at least one embodiment, the catalyst exhibits a catalyst productivity of about 5,000 g / g to about 15,000 g / g as determined by the amount of polymer produced relative to the amount of catalyst introduced to the reactor, such as about 7,500 g / g to about 12,500 g / g, such as about 9,000 g / g to about 11,000 g / g, alternatively about 5,000 g / g to about 7,500 g / g, alternatively about 7,500 g / g, to about 9,000 g / g, alternatively about 9,000 g / g to about 10,000 g / g, alternatively about 10,000 g / g to about 11,000 g / g, alternatively about 11,000 g / g to about 12,500 g / g, alternatively about 12,500 g / g to about 15,000 g / g. Catalyst activity may be determined by the amount of polymer produced with respect to the amount of catalyst introduced to the reactor. Polymer processing

[0083] Polyethylene copolymer resins of the present disclosure may be processed into films suitable for an intended purpose. The films can be formed by any number of known lamination, extrusion, or coextrusion techniques. Any of the blown, tentered, or cast film techniquescommonly used is suitable. For example, a resin composition can be extruded in a molten state through a flat die and then cooled to form a film, in a cast film process. Alternatively, the composition can be extruded in a molten state through an annular die and then blown and cooled to form a tubular, blown film, which can then be used to make sacks or slit and unfolded to form a flat film.

[0084] The extrusion temperatures, die temperatures, and chill roll temperatures are dependent on the composition of the polymeric composition employed, but will generally be within the following ranges for the compositions described herein: extrusion temperature, 170°C to 250°C; die temperature, 170°C to 250°C; and chill roll temperature, 10°C to 65°C. The filmmaking processes can also include embossing rolls to chill and form the film.

[0085] The films can also be unoriented, uniaxially oriented, or biaxially oriented. In one or more embodiments, the multi-layer films can be uniaxially or biaxially oriented. Orientation in the direction of extrusion is known as machine direction (MD) orientation. Orientation perpendicular to the direction of extrusion is known as transverse direction (TD) orientation. Orientation can be accomplished by stretching or pulling a film first in the MD followed by TD orientation. Blown films or cast films can also be oriented by a tenter-frame orientation subsequent to the film extrusion process, again in one or both directions. Orientation can be sequential or simultaneous, depending upon the desired film features. For example, orientation ratios can be about three to about six times the extruded width in the machine direction and between about four to about ten times the extruded width in the transverse direction. Typical commercial orientation processes are BOPP tenter process and blown film.

[0086] In a particular film orientation embodiment, an interdigitating grooved roller assembly is used to simultaneously produce a desirable crinkled surface finish and orient the film. Such processes are described in US Patent 4,368,565. In this process, the film is stretched between two interlocking grooved rollers which are able to both biaxially stretch the film and orient it.

[0087] For multiple-layer films, the materials forming each layer can be coextruded through a coextrusion feedblock and die assembly to yield a film with two or more layers adhered together but differing in composition. Coextrusion can be adapted to cast film or blown film processes. Multiple-layer films can also be formed by combining two or more single layer films using conventional lamination techniques.Polymer blends

[0088] In some embodiments, the polyethylene copolymer resins of the present disclosure can be formulated (e.g., blended) with one or more other polymer components. In some embodiments, those other polymer components are alpha-olefin polymers such as polypropylene or polyethylene homopolymer and copolymer compositions. In some embodiments, those other polyethylene polymers are selected from the group consisting of linear low density polyethylene, high density polyethylene, medium density polyethylene, low density polyethylene, and other differentiated polyethylenes.

[0089] In some embodiments, the formulated blends can contain additives, which are determined based upon the end use of the formulated blend. In some embodiments, the additives are selected from the group consisting of fillers, antioxidants, phosphites, anti-cling additives, tackifiers, ultraviolet stabilizers, heat stabilizers, antiblocking agents, release agents, antistatic agents, pigments, colorants, dyes, waxes, silica, processing aids, neutralizers, lubricants, surfactants, and nucleating agents. In some embodiments, additives are present in an amount from 0.1 ppm to 5 wt %, such as about 0.1 wt% to about 5 wt%, such as about 0.5 wt% to about 4 wt%, such as about 1 wt% to about 3 wt%.

[0090] Polyethylene copolymers of the present disclosure can be optionally blended with one or more processing aids to form a polyethylene blend. Because of the improved properties of polyethylene copolymers of the present disclosure, advantageously, such processing aids can be omitted even in blown films (e.g., films, and particularly blown films, of some embodiments may be free of or substantially free of polymer processing aids, and especially polymer processing aids comprising fluorine; where “substantially free” means free of any intentionally added components, but allowing for up to 100 ppm of such component(s) as impurities). Articles of manufacture

[0091] A polyethylene copolymer resin (or blend thereof) of the present disclosure can be useful in such forming operations as film, sheet, and fiber extrusion and co-extrusion as well as blow molding, injection molding, and rotary molding. Films include blown or cast films formed by co-extrusion or by lamination useful as shrink film, cling film, stretch film, sealing films, oriented films, snack packaging, heavy duty bags, grocery sacks, baked and frozen food packaging, medical packaging, industrial liners, membranes, etc., in food-contact and non-food contact applications. Fibers include melt spinning, solution spinning and melt blown fiber operations for use in woven or non-woven form to make filters, diaper fabrics, medical garments, geotextiles, etc. Extruded articles include medical tubing, wire and cable coatings, pipe, geomembranes, and pond liners. Molded articles include single and multi-layeredconstructions in the form of bottles, tanks, large hollow articles, rigid food containers and toys, etc.

[0092] The polyethylene copolymer resins (or blends thereof) may be formed into monolayer or multilayer films. These films may be formed by any of the conventional techniques including extrusion, co-extrusion, extrusion coating, lamination, blowing and casting. The film may be obtained by the flat film or tubular process which may be followed by orientation in a uniaxial direction or in two mutually perpendicular directions in the plane of the film. One or more of the layers of the film may be oriented in the transverse and / or longitudinal directions to the same or different extents. This orientation may occur before or after the individual layers are brought together. For example a polyethylene copolymer (or blend thereof) layer can be extrusion coated or laminated onto an oriented polypropylene layer or the polyethylene copolymer (or blend thereof) and polypropylene can be coextruded together into a film then oriented. Likewise, oriented polypropylene could be laminated to oriented polyethylene copolymer (or blend thereof), or oriented polyethylene copolymer (or blend thereof) could be coated onto polypropylene then optionally the combination could be oriented even further.

[0093] Films include monolayer or multilayer films. Specific end use films include, for example, blown films, cast films, stretch films, stretch / cast films, stretch cling films, stretch handwrap films, machine stretch wrap, shrink films, shrink wrap films, greenhouse films, laminates, and laminate films. Exemplary films are prepared by any conventional technique known to those skilled in the art, such as for example, techniques utilized to prepare blown, extruded, and / or cast stretch and / or shrink films (including shrink-on-shrink applications).

[0094] In one embodiment, multilayer films (multiple-layer films) may be formed by any suitable method. The total thickness of multilayer films may vary based upon the application desired. A total film thickness of about 5 μm to about 100 μm, such as about 10 μm to about 50 μm, is suitable for most applications. Those skilled in the art will appreciate that the thickness of individual layers for multilayer films may be adjusted based on desired end-use performance, polymer(s) employed, equipment capability, and other factors. The materials forming each layer may be coextruded through a coextrusion feedblock and die assembly to yield a film with two or more layers adhered together but differing in composition. Coextrusion can be adapted for use in both cast film or blown film processes. Exemplary multilayer films have at least two, at least three, or at least four layers. In one embodiment the multilayer films are composed of five to ten layers.

[0095] In some embodiments, multilayer films formed incorporating a polyethylene copolymer resin of the present disclosure can exhibit a 1% secant modulus (machine direction) of about 10 kpsi to about 40 kpsi as determined in accordance with ASTM D-882, such as about 15 kpsi to about 35 kpsi such as about 20 kpsi to about 30 kpsi, alternatively about 10 kpsi to about 15 kpsi, alternatively about 15 kpsi to about 20 kpsi, alternatively about 20 kpsi to about 25 kpsi, alternatively about 25 kpsi to about 30 kpsi, alternatively about 30 kpsi to about 35 kpsi, alternatively about 35 kpsi to about 40 kpsi. In some embodiments, multilayer films formed incorporating a polyethylene copolymer resin of the present disclosure can exhibit a 1% secant modulus (transverse direction) of about 10 kpsi to about 40 kpsi as determined in accordance with ASTM D-882, such as about 15 kpsi to about 35 kpsi such as about 20 kpsi to about 30 kpsi, alternatively about 10 kpsi to about 15 kpsi, alternatively about 15 kpsi to about 20 kpsi, alternatively about 20 kpsi to about 25 kpsi, alternatively about 25 kpsi to about 30 kpsi, alternatively about 30 kpsi to about 35 kpsi, alternatively about 35 kpsi to about 40 kpsi.

[0096] In some embodiments, multilayer films formed incorporating a polyethylene copolymer resin of the present disclosure can exhibit a yield strength of about 0.5 kpsi to about 2 kpsi as determined in accordance with ASTM D-882, such as about 0.75 kpsi to about 1.75 kpsi, such as about 1 kpsi to about 1.5 kpsi, alternatively about 0.5 kpsi to about 0.75 kpsi, alternatively about 0.75 kpsi to about 1 kpsi, alternatively about 1 kpsi to about 1.25 kpsi, alternatively about 1.25 kpsi to about 1.5 kpsi, alternatively about 1.5 kpsi to about 1.75 kpsi, alternatively about 1.75 kpsi to about 2 kpsi.

[0097] In some embodiments, multilayer films formed incorporating a polyethylene copolymer resin of the present disclosure can exhibit an impact resistance of about 200 g to about to about 525 g as determined in accordance with ASTM D-1709, such as about 200 g to about 500 g, such as about 250 g to about 450 g, such as about 300 g to about 400 g, alternatively about 200 g to about 250 g, alternatively about 250 g to about 300 g, alternatively about 300 g to about 350 g, alternatively about 350 g to about 400 g, alternatively about 400 g to about 450 g, alternatively about 450 g to about 500 g, alternatively about 500 g to about 525 g.

[0098] In some embodiments, multilayer films formed incorporating a polyethylene copolymer resin of the present disclosure can exhibit a haze of about 3% to about 7% as determined in accordance to ASTM D-1003, such as about 4% to about 6%, such as about 4.5% to about 5.5%, alternatively about 3% to about 4%, alternatively about 4% to about 4.5%, alternatively about 4.5% to about 5%, alternatively about 5% to about 5.5%, alternatively about 5.5% to about 6%, alternatively about 6% to about 7%.

[0099] In some embodiments, multilayer films formed incorporating a polyethylene copolymer resin of the present disclosure can exhibit a heat seal initiation temperature of about 60 ºC to about 75 ºC as determined in accordance with Example 7, such as about 65 ºC to about 70 ºC, such as about 66 ºC to about 68 ºC.

[0100] In some embodiments, multilayer films formed incorporating a polyethylene copolymer resin of the present disclosure can exhibit a hot tack window of about 80 ºC to about 120 ºC as determined in accordance with Example 8, such as about 90 ºC to about 110 ºC, such as about 95 ºC to about 105 ºC. Examples Example 1: GPC4D

[0101] The distributions and the moments of molecular weight (Mw, Mn, Mw / Mn, etc.), are determined by using a high temperature Gel Permeation Chromatography (Polymer Char GPC-IR) equipped with a multiple-channel band-filter based Infrared detector IR5, an 18-angle Wyatt Dawn Heleos light scattering detector and a 4-capillary viscometer with Wheatstone bridge configuration. Three Agilent PLgel 10-μm Mixed-B LS columns are used to provide polymer separation. Aldrich reagent grade 1,2,4-trichlorobenzene (TCB) with 300 ppm antioxidant butylated hydroxytoluene (BHT) is used as the mobile phase. The TCB mixture isfiltered through a 0.1- m Teflon filter and degassed with an online degasser before enteringthe GPC instrument. The nominal flow rate is 1.0 ml / min and the nominal injection volume is 200 L. The whole system including transfer lines, columns, and viscometer detector arecontained in ovens maintained at 145 C. The polymer sample is weighed and sealed in astandard vial with 80- L flow marker (Heptane) added to it. After loading the vial in theautosampler, polymer is automatically dissolved in the instrument with 8 ml added TCB solvent. The polymer is dissolved at 160°C with continuous shaking for about 2 hour. The concentration (c), at each point in the chromatogram is calculated from the baseline-subtracted IR5 broadband signal intensity (I), using the following equation: c = I, where is the mass constant. The mass recovery is calculated from the ratio of the integrated area of the concentration chromatography over elution volume and the injection mass which is equal to the pre-determined concentration multiplied by injection loop volume. The conventional molecular weight (IR MW) is determined by combining universal calibration relationship with the column calibration which is performed with a series of monodispersed polystyrene (PS) standards ranging from 700 to 10 million g / mol. The MW at each elution volume is calculated with the following equation:logMlog(KPS / K)aPS1 logM a 1 a 1 PS where thefor polystyrene while those without a subscript are the test samples. In this method,PS= 0.67 and KPS= 0.000175 while and K are for ethylene-hexene copolymers as calculated from empirical equations (Sun, T. et al. Macromolecules 2001, 34, 6812), in which a = 0.695 and K = 0.000579(1-0.75Wt), where Wt is the weight fraction for hexane comonomer. It should be noted that the comonomer composition is determined by the ratio of the IR5 detector intensity corresponding to CH2 and CH3 channel calibrated with a series of PE and ethylene-hexene homo / copolymer standards whose nominal values are predetermined by NMR or FTIR. Here the concentrations are expressed in g / cm3, molecular weight is expressed in g / mol, and intrinsic viscosity (hence K in the Mark–Houwink equation) is expressed in dL / g.

[0102] The LS molecular weight (M) at each point in the chromatogram is determined by analyzing the LS output using the Zimm model for static light scattering K o c 1 2A 2 c . R MPRayleigh scattering intensity at scattering angle , c is thepolymer concentration determined from the IR5 analysis, A2 is the second virial coefficient, P( ) is the form factor for a monodisperse random coil, and Ko is the optical constant for thesystem: 4 2n2(dn2 K / dc )oand (dn / dc) is the refractive index increment for the system.The refractive index, n=1.500 for TCB at 145°C and =665 nm. For purposes of the present disclosure and the claims thereto (dn / dc) = 0.1048 for ethylene-hexene copolymers.

[0103] A high temperature Polymer Char viscometer, which has four capillaries arranged in a Wheatstone bridge configuration with two pressure transducers, is used to determine specific viscosity. One transducer measures the total pressure drop across the detector, and the other, positioned between the two sides of the bridge, measures a differential pressure. The specific viscosity,s, for the solution flowing through the viscometer is calculated from their outputs. The intrinsic viscosity, [ ], at each point in the chromatogram is calculated from theequation [ ]= s / c, where c is concentration and is determined from the IR5 broadband channeloutput. Example 2: Temperature rising elution fraction (TREF)

[0104] Comonomer distribution reflecting a similar degree of comonomer incorporation on polymer chains of varying length of the polyethylene copolymer, which is quantified in the composition distribution breadth index (CDBI). For instance, polyethylene comonomers of various embodiments have CDBI of 70% or more, such as 75% or more, such as 80% or more, 85% or more, or even 90% or more. CDBI is defined as the weight percent of the copolymer molecules having a comonomer content within 50% of the median total molar comonomer content (i.e., within + / -25% of the median), and it is referenced, e.g., in U.S. Patent 5,382,630. In general, copolymers with a broader distribution result in a lower CDBI, while a theoretical copolymer with exactly the same relative comonomer content across all different lengths of polymer chains would have a CDBI of 100%. The CDBI of a copolymer is readily determined utilizing a technique for isolating individual fractions of a sample of the copolymer. One such technique is generation of a solubility distribution curve using Temperature Rising Elution Fraction (TREF), as described in WO 1993003093 (which in turn references Wild, et al., J. Poly. Sci., Poly. Phys. Ed., vol.20, p.441 (1982) and U.S. Patent No. 5,008,204 in this regard). All three of the foregoing publications are incorporated herein by reference. Alternatively, the narrow comonomer distribution can be reflected in the T75- T25value, wherein T25 is the temperature at which 25% of the eluted polymer is obtained and T75 is the temperature at which 75% of the eluted polymer is obtained, both in a TREF experiment as described in US2019 / 0119413 (especially in paragraphs

[0055] –

[0058] thereof, which description is incorporated by reference herein). A narrow distribution is reflected in the relatively small difference in the T75 - T25 value being less than 10°C, such as within the range from 4 to 10oC, such as from a low of any one of 4, 4.5, 5, 5.5, or 6oC to a high of any one of 10, 9.5, 9, 8.5, 8, 7.5, 7, or 6.5oC, such as 5.8oC to 7oC, alternatively 7oC to 9oC, with combinations from any low to any high contemplated (provided the high end is greater than the low end).

[0105] Furthermore, TREF may be used to characterize the broad orthogonal comonomer distribution (BOCD) of a polyethylene copolymer resin of the present disclosure. For example, the polyethylene composition may have the same BOCD characteristics for embodiments described in (and determined in the same manner as detailed in) Paragraphs

[0051] -

[0055] and

[0160] of WO2019 / 083609, the description of which is incorporated by reference herein. This includes a T75– T25value in accordance with the embodiments described in Paragraphs

[0051] -

[0055] , an M60 / M90 value in accordance with those in Paragraph

[0054] , and / or an F80 value per Paragraph

[0055] of said reference, as determined by the TREF-LS method described therein.

[0106] The breadth of the composition distribution can be characterized by the T75- T25 value, wherein T25is the temperature at which 25% of the eluted polymer is obtained and T75is the temperature at which 75% of the eluted polymer is obtained in a TREF experiment as described in WO2019 / 083609. The composition distribution is further characterized by the F80value, which is the fraction of polymer that elutes below 80°C in a TREF-LS experiment as described herein. A higher F80value indicates a higher fraction of comonomer in the polymer molecule.

[0107] An orthogonal composition distribution is defined by a M60 / M90value that is greater than 1, wherein M60 is the molecular weight of the polymer fraction that elutes at 60°C in a TREF-LS experiment and M90is the molecular weight of the polymer fraction that elutes at 90°C in a TREF-LS experiment as described herein. Example 3: Small angle oscillatory shear

[0108] Rheological data such as “Complex shear viscosity ( *),” reported in Pascalseconds, can be measured at 0.01 rad / sec and 100 rad / sec. Complex shear viscosity and other rheological measurements can be obtained from small angle oscillatory shear (SAOS) experiments. For instance, complex shear viscosity can be measured with a rotational rheometer such as an Advanced Rheometrics Expansion System (ARES-G2 model) or Discovery Hybrid Rheometer (DHR-3 Model) using parallel plates (diameter=25 mm) in a dynamic mode under nitrogen atmosphere. The rheometer can be thermally stable at 190°C for at least 20 minutes before inserting compression-molded specimen onto the parallel plates. To determine the specimen’s viscoelastic behavior, a frequency sweep in the range from 0.01 to 628 rad / s can be carried out at a temperature of 190°C under constant strain that does not affect the measured viscoelastic properties. The sweep frequencies are equally spaced on a logarithmic scale, so that 5 frequencies are probed per decade. Depending on the molecular weight and temperature, strains of 3% can be used and linearity of the response is verified. A nitrogen stream is circulated through the oven to minimize chain extension or cross-linking during the experiments. The specimens can be compression molded at 190°C, without stabilizers. A sinusoidal shear strain can be applied. The shear thinning slope (STS) can be measured using plots of the logarithm (base ten) of the dynamic viscosity versus logarithm (base ten) of the frequency. The slope is the difference in the log(dynamic viscosity) at afrequency of 100 s 1 and the log(dynamic viscosity) at a frequency of 0.01 s 1 divided by 4. Thecomplex shear viscosity ( *) versus frequency ( ) curves can be fitted using the Carreau-Yasuda model: *- = ( 0- )*(1 + ( )a) (n-1) / a.

[0109] The five parameters in this model are:0, the zero-shear viscosity; , the relaxation time; and n,,rate viscosity; and a, the transition index. The zero-shear viscosity is the value at a plateau in the Newtonian region of the flow curve at a low frequency, where the dynamic viscosity is independent of frequency. The relaxation time corresponds to the inverse of the frequency at which shear-thinning starts. The power-law exponent describes the extent of shear-thinning, in that the magnitude of the slope of the flowcurve at high frequencies approaches n-1 on a log( *)-log( ) plot. For Newtonian fluids, n=1and the dynamic complex viscosity is independent of frequency.

[0110] In addition to dynamic and complex viscosity (each in Pascal seconds), at each frequency sweep in the SAOS experiment, various other parameters are collected, including storage modulus (Pa), Loss modulus (Pa), Complex Modulus (Pa), tan(delta), and phase angle. Charting the phase angle versus the complex shear modulus from the rheological experiment yields van Gurp Palmen plots useful to extract some information on the molecular characteristics e.g., linear vs. long chain branched chains, type of long chain branching, polydispersity (Dealy, M. J., Larson, R. G., “Structure and Rheology of Molten Polymers”, Carl Hanser Verlag, Munich 182-183 (2006). It has been also suggested that VGP-plots can be used to reveal the presence of long chain branching in polyethylene. See Trinkle, S., Walter, P., Friedrich, C. “Van Gurp-Palmen plot II—Classification of long chain branched polymers by their topology”, in 41 Rheol. Acta 103-113 (2002).

[0111] “Shear Thinning Ratio”, which is reported as a unitless number, is characterized by the decrease of the complex viscosity with increasing shear rate. Herein, shear thinning can be determined as a ratio of complex viscosity at a frequency of 0.01 rad / s to the complex viscosity at a frequency of 100 rad / s. Example 4: Melt Index, High Load Melt Index, and Melt Index Ratio

[0112] The melt index (I2), high load melt index (I21), and melt index ratio (I21 / I2) of each polyethylene copolymer resin sample were determined in accordance to ASTM D1238. Example 5: Density Determination and Sample Preparation

[0113] The density of each of polyethylene copolymer resin was determined in accordance to ASTM D1505. Samples derived from the polyethylene copolymer resin were molded under ASTM D4703-10a, Procedure C, and then conditioned under ASTM D618-08 (23 ºC ± 2 ºC and 50% ± 10% relative humidity) for 40 hours before testing. Example 6: Mechanical, Physical, and Visual Analysis

[0114] Test samples were subjected to various mechanical, physical, and visual analysis. Analysis of such properties includes determining a sample’s the 1% secant modulus (ASTM D-882, using a 15 mm wide strip), yield strength (ASTM D-882, using a 15 mm wide strip), impact resistance (ASTM D-1709, phenolic, method A), and haze (ASTM D-1003). Example 7: Heat Seal Analysis

[0115] Test samples were prepared as 1 inch film strips of 1 mil gauge. The samples were sealed at various temperatures under 73 psi (0.5 N / mm2) for approximately 1 second. Following conditioning for 40 hours at approximately 20 ºC and approximately 50% relative humidity (± 10%), the sealed test sample were tested in a T-joint peel mode at a pulling speed of approximately 20 inch / min. Example 8: Hot Tack Analysis

[0116] Test samples were prepared as 1 inch film strips of 1 mil gauge. The samples were sealed at various temperatures under 73 psi (0.5 N / mm2) for approximately 0.5 seconds. After a 0.4 second delay, the sealed sample were pulled at 200 mm / s in T-joint peel mode. Example 9: Formation of Exemplary Polyethylene Copolymer Resins

[0117] Exemplary polyethylene copolymer resins were formed in a gas phase reactor (e.g., an EMTEC R124 gas phase pilot plant reactor) using varied H2 gas concentrations, varied flow ratios of olefin comonomer (e.g., 1-hexene) and ethylene into the gas phase reactor (C6:C2), varied ICA (e.g., pentane) concentration within the reactor, and varied catalyst feed rate into the reactor. Three different polyethylene copolymer resins (e.g., I1, I2, and I3) were formed in accordance to the parameters and / or input values set forth in Table 1. Table 1: Summary of input parameters and / or variables used to formulate exemplary polyethylene copolymer resins I1, I2, and I3. Variable Units I1 I2 I3 B T t °F 1 1 1 0 9 9 7 6 4 1 3 1Example 10: Properties of Exemplary Polyethylene Copolymer Resins

[0118] The densities, melt indices (I2), melt index ratios (I21 / I2), molecular weights, and olefin comonomer integration of each of the exemplary resins (I1, I2, and I3) were determined in accordance to the respective test methods described above. The values determined for each of the exemplary resins were further compared to similar polyethylene copolymer resins (C4 and C5) that are commercially available and commonly used in cast film sealing layer applications. The properties of each of the resins are summarized in Table 2. Table 2: Summary of properties of various polyethylene copolymer resins Melt i Hexene Ex.Densityndex 1iMIR Mn Mw Mz Mw / Mncontent )s ca e e e e o a e , e e e pa y es s , , a e hibit slightly higher density values and melt indices in comparison to the commercially available resins (C4 and C5). Without being bound by theory, such increased properties are advantageous to the materials’ mechanical properties and seal ability.

[0120] Additionally, the higher melt indices of the exemplary resins (I1, I2, and I3) endow such materials with a lower zero shear viscosity than the commercially available resins (4 and C5), as determined via results small angle oscillatory shear experiments, as illustrated in Figure 2. The low zero shear viscosities of the exemplary resins (I1, I2, and I3) are associated with a higher extent of polymer chain mobility, enhancing the diffusion of individual polymer chains and easing the flow of the molten resin during the sealing process. Without being bound by theory, such viscoelastic properties allow for improved seal caulkability (e.g., the ability of a molten resin to flow around small surface defects or contaminants to still form a reliable seal between two films).

[0121] Without being bound by theory, seal ability and seal performance are related to the melting temperature of the polymer resin. The melting temperature of the polymer resin is related to the olefin comonomer (e.g., 1-hexene) integration and orientation within the polyethylene copolymer resin, which can be determined by GPC4D (as shown in Figure 3) andTREF (as shown in Figure 4). As determined from the GPC4D results shown in Figure 3, the exemplary resins (I1, I2, and I3) exhibit slight broad orthogonal composition distribution. That is to say, that the olefin comonomer integrated within the exemplary resins (I1, I2, and I3) is more concentrated / integrated within the polymer population within the resin having a higher molecular weight. Without being bound by theory, such olefin comonomer integration and orientation within the polymer resin may result in improved hot tack performance by allowing the higher viscosity high molecular weight portion of the resin to melt at a lower temperature. Furthermore, the exemplary resins (I1, I2, and I3) have a broad TREF elution temperature range and a broad low temperature tail, as shown in Figure 4. Without being bound by theory, such an elution temperature range and a broad low temperature tail correspond to a lower seal initiation temperature tail, even while holding the overall density constant. Example 11: Preparation and Analysis of Blown Polymer Films

[0122] Polymer films were produced on an Alpine II coextruded blown film line using a film gauge of 2 mil, a blowup ratio of 2.5, a die gap of 60 mil, a frostline height of 34 in., a line speed of 88 ft / min, a die diameter of 250 mm, a total output of 330 lbs / hr, and a die temperature of 400 ºF. The film layer structure was 1:2:1 wt:wt:wt of A:B:C, where A is a sealing layer (e.g., exemplary resins I1, I2, and I3, commercially available resins C4 and C5, or a blend derived therefrom), B is a core layer, and C is a skin layer. The formulation of layer B was fixed as 100% of Enable 2705 MC (e.g., an ethylene / 1-hexene copolymer resin produced by ExxonMobil), and the formulation of layer C was fixed as 75% Exceed 1018 MA (e.g., an ethylene / 1-hexene copolymer resin produced by ExxonMobil) + 25% Enable 2005HE (e.g., an ethylene / 1-hexene copolymer resin produced by ExxonMobil). The mechanical, physical, and visual properties of the resulting material are summarized in Table 3.Table 3: Summary of mechanical, physical, and visual properties of blown polymer films. 1% 1% Secant Secant Yield str Dart Ex L r A f rm l ti n m d l m d l ength H z (%) im t, . ., , I7, and I8) incorporating an exemplary polymer resin (I1, I2, and I3) as the sealing layer A generally results in stiffer polymer films than those polymer films (e.g., C10 and C11) formed using the commercially available resins (C4 and C5) as the sealing layer A, as evidenced by their higher 1% secant moduli in either the machine direction (MD), the transverse direction (TD), or both. This trend is still present, although diluted, for polymer films (e.g., I9 and C12) implementing a blend of polymer resin I1 or C4 with a majority of Exceed 1018 MA. It is common for film manufacturers to blend a low density sealing resin with a comparatively higher density linear, low density polyethylene (LLDPE) resin in order to maintain other mechanical properties and to potentially save cost. Additionally, the MD yield strength of polymer films (e.g., I6, I7, and I8) incorporating an exemplary polymer resin (I1, I2, and I3) as the sealing layer A is similarly greater than those polymer films formed (e.g., C10 and C11) using the commercially available resins (C4 and C5) as the sealing layer A, while the dart impact is lower. These property trends primarily reflect the effects of using the exemplary polymer resins (I1, I2, and I3) as the sealing layer A of a polymer film. As such, the exemplary polymer resins (I1, I2, and I3) can behave more like a typical approximately 0.908 g / cm3density metallocene polyethylene product compared to a typical approximately 0.903 g / cm3density product. Example 12: Sealing Performance of Blown Polymer Films

[0124] The sealing properties of polymer films I6, I7, I8, C10, and C11 are illustrated in Figures 5A – 5B, and the sealing properties of polymer films I9 and C12 are summarized in Figures 6A – 6B. Figures 5A – 5B and Figures 6A – 6B demonstrate that using an exemplarypolymer resin (I1, I2, and I3) as the sealing layer A of a polymer film (e.g., I6, I7, I8, and I9) allows for maintained low seal initiation temperature and high hot tack strength over a broad range temperature window, even when designed to have a higher density than that of the commercially available resins (C4 and C5). As such, the polymer films (e.g., I6, I7, I8, and I9) formed using an exemplary polymer resin (I1, I2, and I3) as the sealing layer A exhibit near equivalent sealing performance to those polymer films (e.g., C10, C11, and C12) formed using the commercially available resins (C4 and C5) as the sealing layer A. Furthermore, the polymer films (e.g., I6, I7, I8, and I9) formed using an exemplary polymer resin (I1, I2, and I3) as the sealing layer A benefit from the higher density of the exemplary polymer resin (I1, I2, and I3), the higher film stiffness and yield strength, lower susceptibility to blocking, and lower coefficients of friction. Such advantageous properties can allow for mechanically congruent layers of a polymer film and polymer films with increased sealing performance. Example 13: Preparation and Analysis of Cast Polymer Films

[0125] Polymer films were produced on a SML coextruded cast film line using a film gauge of 50 μm, a die gap of 0.7 mm, a frost line length of 5 in., a line speed of 100 m / min, a die width of 1.38 m, a total output of 380 lbs / hr, and a die temperature of 245 ºC. The film layer structure was 1:2:1 wt:wt:wt of A:B:C, where A is a sealing layer, B is a core layer, and C is a skin layer. The layer structure is achieved with a 5 extruder, 7 layer die configuration where the middle 5 layers are composed of layer B. The formulation of layer C was fixed as 80% LLDPE + 20% linear low density polyethylene (LDPE). The mechanical, physical, and visual properties of the resulting material are summarized in Table 4.Table 4: Summary of mechanical, physical, and visual properties of cast polymer films. 1% Seca 1% ExLayer A / Layer Bnt m d l Secant Yield tr n th Haze Dart impact

[0126] As is evidenced by the results summarized in Table 4, polymer films (e.g., I13, I14, and I15) incorporating a blend of an exemplary polymer resin (I1, I2, and I3) and LDPE as the sealing layer A and Exceed 3518 PA (e.g., an ethylene / 1-hexene copolymer resin produced by ExxonMobil) as the core layer B exhibit comparable mechanical and physical properties to those polymer films (e.g., C16 and C17) incorporating a blend of commercially available resin (C4 and C5) and LDPE as the sealing layer A and Exceed 3518 PA as the core layer B. Furthermore, polymer films (e.g., I18) incorporating a blend of an exemplary polymer resin (e.g., I1) and LDPE as the sealing layer A and a blend of Exceed 3518 PA and Exceed 4536 PA (e.g., an ethylene / 1-hexene copolymer resin produced by ExxonMobil) as the core layer B exhibit comparable mechanical and physical properties to those polymer films (e.g., C19)incorporating a blend of commercially available resin (e.g., C5) and LDPE as the sealing layer A and a blend of Exceed 3518 PA and Exceed 4536 PA as the core layer B. However, polymer films (e.g., I20 and I21) incorporating Exceed 3518 PA as the sealing layer A and a blend of an exemplary polymer resin (I1 and I2), LDPE, and LLDPE (50 wt%:20 wt%:30 wt%) as the core layer B exhibit decreased mechanical and physical properties as compared to those polymer films (e.g., C22) incorporating Exceed 3518 PA as the sealing layer A and a blend of an commercially available resin (C5), LDPE, and LLDPE (30 wt%:30 wt%:40 wt%) as the core layer B. Example 14: Sealing Performance of Cast Polymer Films

[0127] In terms of sealing performance in the cast polymer films (e.g., I13, I14, I15, C16 and C17), the exemplary polymer resins (I1, I2, and I3) are comparable to the lower density commercially available resin (e.g., C4). However, the cast polymer films (e.g., C17) incorporating the higher density commercially available resin (e.g., C5) tend to exhibit more favorable seal initiation temperatures and a broader hot tack window. This trend can be observed in Figures 7A – 7B, which shows the results from film structures with 25 wt% LDPE blended into the sealing layer with either one of the exemplary resins (I1, I2, and I3) or one of the commercially available resins (C4 and C5). A similar trend can be observed in Figures 8A – 8B, which illustrates the sealing behavior of similarly structured polymer films (e.g., I18 and C19) incorporating a higher density resin blend as the core layer B.

[0128] In addition, polymer films (e.g., I20 and I21) incorporating one of the exemplary resins (I1 or I2) blended with LDPE as the core layer B exhibit increased sealability when compared to a polymer film (e.g., C22) of similar structure using a blend of a commercially available resin (C5) and LDPE as the core layer, as shown in Figures 9A – 9B. As such, the sealing behaviors illustrated in Figures 5A – 9B suggest that polymer film properties (e.g., seal ability and mechanical performance) are predicated on polymer blend compositions used in the various layers of the polymer film.

[0129] Additionally, the trends in sealability and seal performance illustrated in Figures 5A – 9B suggest that the exemplary resins of the present disclosure (e.g., I1, I2, and I3) can be integrated into the sealing layer A of the resulting polymer films to further improve sealing performance. This is particularly true in instances incorporating blends of LLDPE and one or more exemplary resins of the present disclosure (e.g., I1, I2, and I3). That being said, in instances wherein higher mechanical property polymer films are desired, it is advantageous to incorporate blends of higher density polyethylene resins with exemplary resins of the present disclosure (e.g., I1, I2, and I3).

[0130] Overall, processes of the present disclosure allow for the production of polyethylene copolymer resins having a low seal initiation temperature, while also maintaining the mechanical and rheological properties desirable for manufacturing articles, such as multi-layer films. For example, the broad orthogonal comonomer distribution (e.g., comonomer concentrated on the high molecular weight polymer fraction) increases polymer chain mobility to produce a reduced seal initiation temperature while also maintaining a material density sufficient for favorable mechanical property retention. Furthermore, the polyethylene copolymer resins could be integrated into multi-layer film fabrication processes. Multi-layer films that incorporate the polyethylene resins of the present disclosure as the sealing layer can exhibit comparable sealability and enhanced mechanical properties to those formed using commercially available resins. The polyethylene copolymer resin compositions of the present disclosure, and processes thereof, can offer the seal ability without sacrificing the mechanical properties of the material.

[0131] The phrases, unless otherwise specified, "consists essentially of" and "consisting essentially of" do not exclude the presence of other steps, elements, or materials, whether or not, specifically mentioned in this specification, so long as such steps, elements, or materials, do not affect the basic and novel characteristics of the present disclosure, additionally, they do not exclude impurities and variances normally associated with the elements and materials used.

[0132] For the sake of brevity, only certain ranges are explicitly disclosed herein. However, ranges from any lower limit may be combined with any upper limit to recite a range not explicitly recited, as well as, ranges from any lower limit may be combined with any other lower limit to recite a range not explicitly recited, in the same way, ranges from any upper limit may be combined with any other upper limit to recite a range not explicitly recited. Additionally, within a range includes every point or individual value between its end points even though not explicitly recited. Thus, every point or individual value may serve as its own lower or upper limit combined with any other point or individual value or any other lower or upper limit, to recite a range not explicitly recited.

[0133] All documents described herein are incorporated by reference herein, including any priority documents and or testing procedures to the extent they are not inconsistent with this text. As is apparent from the foregoing general description and the specific embodiments, while forms of the present disclosure have been illustrated and described, various modifications can be made without departing from the spirit and scope of the present disclosure. Accordingly, it is not intended that the present disclosure be limited thereby. Likewise, the term “comprising” is considered synonymous with the term “including” for purposes of UnitedStates law. Likewise whenever a composition, an element or a group of elements is preceded with the transitional phrase “comprising,” it is understood that we also contemplate the same composition or group of elements with transitional phrases “consisting essentially of,” “consisting of,” “selected from the group of consisting of,” or “is” preceding the recitation of the composition, element, or elements and vice versa.

[0134] While the present disclosure has been described with respect to a number of embodiments and examples, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope and spirit of the present disclosure.

Claims

CLAIMS What is claimed is:

1. A polyethylene copolymer, comprising: ethylene units; and about 12.5 wt% to about 15 wt% comonomer units based on the weight of the ethylene units and the comonomer units, the polyethylene copolymer having: a density of about 0.907 g / cm3to about 0.913 g / cm3, as determined by ASTM D1505; a melt index (I2) of about 4 g / 10 min to about 8 g / 10 min, as determined by ASTM D1238.

2. The polyethylene copolymer of claim 1, wherein the olefin comonomer units comprise 1- hexene.

3. The polyethylene copolymer of claim 1 or claim 2, wherein the polyethylene copolymer comprises a number average molecular weight (Mn) of about 25 kDa to about 30 kDa, as determined by polymer char gel permeation chromatography equipped with multiple detectors (GPC4D).

4. The polyethylene copolymer of claim 1 or any of claims 2-3, wherein the polyethylene copolymer comprises a molecular weight distribution (MWD) of about 2.5 to about 3.0, as determined by polymer char gel permeation chromatography equipped with multiple detectors (GPC4D).

5. The polyethylene copolymer of claim 1 or any of claims 2-4, wherein the polyethylene copolymer further comprises a high load melt index (I21) of about 70 g / 10 min to about 120 g / 10 min, as determined by ASTM D1238.

6. The polyethylene copolymer of claim 1 or any of claims 2-5, wherein the polyethylene copolymer has a T75-T25value that is 15 ºC or greater.

7. A polymer film, comprising: a first layer, the first layer comprising a first polyethylene copolymer, the first polyethylene copolymer having: a density of about 0.907 g / cm3to about 0.913 g / cm3, wherein the density of the first polyethylene copolymer is determined by ASTM D1505, a melt index (I2) of about 4 g / 10 min to about 8 g / 10 min, wherein the I2of the first polyethylene copolymer is determined by ASTM D1238, and an olefin comonomer content of about 12.5 wt% to about 15 wt%; a second layer disposed on the first layer, the second layer comprising a second polyethylene copolymer; and a third layer disposed on the second layer, the third layer comprising a third polyethylene copolymer; wherein the polymer film has a heat seal initiation temperature of about 60 ºC to about 75 ºC 8. The polymer film of claim 7, wherein the olefin comonomer is 1-hexene.

9. The polymer film of claim 7 or claim 8, wherein the first polyethylene copolymer comprises a number average molecular weight (Mn) of about 25 kDa to about 30 kDa, as determined by polymer char gel permeation chromatography equipped with multiple detectors (GPC4D).

10. The polymer film of claim 7 or any of claims 8-9, wherein the first polyethylene copolymer comprises a molecular weight distribution (MWD) of about 2.5 to about 3.0, as determined by polymer char gel permeation chromatography equipped with multiple detectors (GPC4D).

11. The polymer film of claim 7 or any of claims 8-10, wherein the first polyethylene copolymer further comprises a high load melt index (I21) of about 70 g / 10 min to about 120 g / 10 min, as determined by ASTM D1238.

12. The polymer film of claim 7 or any of claims 8-11, wherein the polyethylene copolymer has a T75-T25value that is 15 ºC or greater.

13. The polymer film of claim 7 or any of claims 8-12, wherein the polymer film comprises a heat seal initiation temperature of about 65 ºC to about 70 ºC.

14. The polymer film of claim 7 or any of claims 8-13, wherein the polymer film comprises a hot tack window of about 80 ºC to about 120 ºC.

15. A method of producing a polyethylene copolymer, the method comprising: providing a feed stream to a reactor, the feed stream comprising an ethylene monomer and an olefin comonomer, wherein the olefin comonomer and ethylene monomer are provided to the reactor at a flow ratio of olefin comonomer:ethylene of about 0.15 lb / lb to about 0.18 lb / lb; providing H2 gas to the reactor, wherein the concentration of H2 gas provided to the reactor is about 330 mol ppm to about 390 mol ppm; introducing a catalyst composition to the reactor, wherein the catalyst has a catalyst productivity of about 5,000 g / g to about 15,000 g / g; and polymerizing the ethylene monomer and olefin comonomer, wherein the reactor is operated at a temperature of about 50 °C to about 100 °C and a pressure of about 250 psig to about 350 psig.

16. The method of claim 15, wherein the feed stream further comprises an induced condensing agent (ICA), the ICA being selected from one or more of C1-C6alkanes.

17. The method of claim 16, wherein the ICA concentration provided to the reactor is about 1.5 mol% to about 3 mol% based on the total mol% of each of the ethylene, the olefin comonomer, the H2 gas, the catalyst, and ICA provided to the reactor.

18. The method of claim 15 or any of claims 16-17, wherein the ethylene concentration provided to the reactor is about 45 mol% to about 75 mol% based on the total mol% of each of the ethylene, the olefin comonomer, the H2 gas, the catalyst, and ICA provided to the reactor.

19. The method of claim 15 or any of claims 16-18, wherein the ethylene partial pressure within the reactor is about 150 psi to about 210 psi.

20. The method of ciaim 15 or any of claims 16-19, wherein H2 gas is provided to the reactor at a gas ratio (H2: ethylene) of about 5 mol ppnv'mol to about 7 mol ppm / mol... 4] ■■

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